1. Field of the Invention
The present invention relates to a relay communication system capable of communicating with a communication device in another local area network (LAN) over a wide area network (WAN). In particular, the present invention relates to a technique of operating, from the communication device in a certain LAN, resources held by a communication device in another LAN.
2. Description of the Related Art
A communication technique referred to as VPN (Virtual Private Network) has been proposed. Through the use of such communication technique, another LAN at a remote location can be used as if it is a directly connected network. For instance, the terminals connected to the LAN of a plurality of branch offices established in every region can communicate over the Internet.
However, this type of system tends to be a rigid system in terms of virtually building the network. Thus, it is not easy to build a system having expandability and flexibility, and systems that have been proposed up to now have advantages and disadvantages in function, cost, and the like.
If resources are provided in the same LAN, those resources can be easily shared, etc., among a plurality of terminals since resources are normally managed by the same protocol, and the system configuration is not all that complex. However, if the communication system extends over a plurality of LANs over the WAN, when desiring to share resources such as folders and files among a plurality of terminals or to delete files held by a certain terminal from another terminal, such desire cannot be easily satisfied. This is even more of a problem when the protocols used in the respective LAN differ.
Although the resources held by each terminal constantly change by deletion, movement, and the like, it is not easy to dynamically respond to such changes. Moreover, a mechanism for providing such dynamically changing information to users in a format of higher versatility does not exist.